功能高分子

本文简述了功能高分子的发展,合成途径以及所谓的高分子效应。对该领域内所涉及的各类功能高分子的性质、合成、应用及发展前景等作了概要介绍。内容包括具有分离功能的高分子、高分子试剂、高分子催化剂、光活性高分子、磁性高分子、能量转换及储能材料、生物医用材料、高分子药物、高分子液晶及一些其他功能高分子材料。     

从诺贝尔奖看高分子百年*

从高分子学科确立到现在已经经历了整整一个世纪。围绕高分子领域的历次诺贝尔奖,重点回顾了“高分子”概念的确立、高分子合成化学、高分子理论、功能高分子等领域的里程碑事件,分析了高分子学科的未来发展趋势。     

高分子物理课程中影响高分子柔顺性因素的教学实践

针对高分子物理课程中影响高分子链柔顺性的高分子链结构方面因素的讲授,结合不同高分子材料的用途,形象地说明了高分子链柔顺性对高分子材料性能的影响,使学生真切地了解到高分子链的柔顺性决定了高分子材料的不同用途,这种理论联系实际的教学方法避免了抽象的死记硬背,可以加深学生的感性认识,取得了良好的教学效果。     

高分子科学第一课教学点滴

高分子科学是蓬勃发展的高分子材料工业的理论基础,对其深刻理解、灵活运用是进行高分子工业实践的前提条件,然而当前高分子专业学生中存在对高分子科学不感兴趣或者"偏见"现象,影响了高分子科学的教学效果和后续实践,因此,开展高分子科学教学研究,对培养具备深厚高分子科学理论与应用兴趣的专门人才具有重要意义。作者阐述了为激发学生长久、自主学习兴趣进行的高分子科学第一课教学改进体会,即强调高分子材料的价值宣讲、突出高分子知识的应用特性和演义高分子科学丰富历史,结合知识性、故事性和实际性多维度教学,引导同学们走近高分子、走进高分子、爱上高分子。     

高分子负载金属催化剂的高分子效应

本文评述了高分子负载金属催化剂的分类及其高分子效应,重点评述了高分子负载金属络合物催化剂的载体功能基效应,多功能协同效应,高分子场效应和高分子基体效应,对高分子分散金属催化剂的高分子效应研究也作了一定的综述。     

非高分子专业《高分子化学与物理》教学中的几点体会

高分子科学已渗透于各个领域与学科,形成了一个无法替代的交叉学科,因此,工科化学或材料相关专业纷纷开设高分子相关课程。《高分子化学与物理》作为哈尔滨工程大学材料化学专业的主干课之一,包括高分子化学和高分子物理两个侧面,其中高分子化学部分侧重高分子合成的基本理论知识,高分子物理部分则侧重于高分子的结构与性能。本文分析了高分子化学与物理的课程特点,总结了在课堂教学中采取的行之有效的措施和教学尝试,介绍了在课堂教学过程中,如何导入心理教育,提高学生的学习兴趣。     

电光高分子研究进展

电光高分子是二阶非线性光学材料的重要组成部分,目前的研究重点主要在于合成具有高二阶非线性光学效应和取向稳定性以及低光学损耗的电光高分子,以满足高性能光学器件的制作要求。最近,电光高分子的设计与合成已经取得了很大的进展,例如结合"位分离"原理,利用高分子良好的加工性,获得了一些具有较好综合性能的高分子,可以较为有效地将小分子发色团的高β值转换为高分子大的宏观电光效应。本文综述了近几年来电光高分子的研究进展,主要包括线型电光高分子、树枝状电光高分子和超支化高分子。     

高分子单链的研究进展

随着纳米科技在高分子领域的不断升温,高分子单链凝聚态的研究引起了人们的广泛重视。高分子单链以纳米尺度的微粒孤立存在,不存在分子链之间的几何缠结。本文综述了近年来国内外高分子单链的研究进展。首先介绍了高分子单链的主要制备方法如喷雾法、冷冻干燥法、微乳液聚合法、反向沉淀法以及表面扩展膜法,接着详细介绍了高分子单链的表征技术及高分子链构象的计算机模拟技术,最后介绍了高分子单链及单分子胶束在制备金属纳米粒子领域的应用,并展望了高分子单链的研究领域和方向。     

《功能高分子材料》

全书共分17章，结合功能高分子材料的结构与性能、制备方法及应用领域，对离子交换树脂，吸附树脂，离子交换纤维和活性碳纤维，高分子膜分离材料，高分子色谱固定相，高分子试剂，高分子负载催化剂，导电高分子材料，电效发光聚合物材料，非线性光学高分子材料，液晶高分子材料，感光高分子材料，医用高分子材料，环境敏感高分子材料，高分子电解质，高分子染料，淀粉，纤维素衍生物高分子等进行了详细论述。[第一段]     

从高分子化学与衣食住行到高科技发展

本文围绕国际化学年的主题,介绍高分子科学与人类衣食住行、国民经济各个方面的密切关系,结合高分子发展历程、高分子产业现状和高分子学科前沿与发展趋势,概述了高分子科学与技术的基本情况。     

Simulation and experimental demonstration of the electric field assisted electroporation microchip for in vitro gene delivery enhancement

Simulation and experimental demonstration of the in vitro gene delivery enhancement using electrostatic forces and electroporation (EP) microchips were conducted. Electroporation is a technique with which DNA molecules can be delivered into cells using electric field pulses. This study demonstrates that plasmid DNA can be attracted to the cell surfaces at the specific regions using an electrostatic force. Therefore, the DNA concentration on the cell surface is dramatically increased, which highly enhances the gene transfection efficiency compared to that without an attracting-electric field. The electrostatic force can be designed into specific regions, where the DNA plasmids are attracted to, to provide the region-targeting function. In this micro-device, the top electrode and the interdigitated electrodes provided the DNA attracting-electric field, and the interdigitated electrodes provided adequate electric fields for the electroporation process on the chip surface. Using the EP microchip, cells could be manipulated in situ without detachment if adherent cells were used for electroporation. Five different cells of two different types, primary cell and cell line, were successfully transfected under multi-pulse or single pulse electric field stimulation without applying an attracting-electric field. This study simulated and analyzed the electric field distributions at the DNA attracting and electroporation processes, and successfully demonstrated that the electrostatic force attracted DNA plasmids to specific regions and highly enhanced the gene delivery. In summary, this EP microchip should provide many potential applications for gene therapy.     

Real time electroporation control for accurate and safe in vivo non-viral gene therapy

In vivo cell electroporation is the basis of DNA electrotransfer, an efficient method for non-viral gene therapy using naked DNA. The electric pulses have two roles, to permeabilize the target cell plasma membrane and to transport the DNA towards or across the permeabilized membrane by electrophoresis. For efficient electrotransfer, reversible undamaging target cell permeabilization is mandatory. We report the possibility to monitor in vivo cell electroporation during pulse delivery, and to adjust the electric field strength on real time, within a few microseconds after the beginning of the pulse, to ensure efficacy and safety of the procedure. A control algorithm was elaborated, implemented in a prototype device and tested in luciferase gene electrotransfer to mice muscles. Controlled pulses resulted in protection of the tissue and high levels of luciferase in gene transfer experiments where uncorrected excessive applied voltages lead to intense muscle damage and consecutive loss of luciferase gene expression.     

Binding and condensation of plasmid DNA onto functionalized carbon nanotubes: toward the construction of nanotube-based gene delivery vectors

Carbon nanotubes (CNTs) constitute a class of nanomaterials that possess characteristics suitable for a variety of possible applications. Their compatibility with aqueous environments has been made possible by the chemical functionalization of their surface, allowing for exploration of their interactions with biological components including mammalian cells. Functionalized CNTs (f-CNTs) are being intensively explored in advanced biotechnological applications ranging from molecular biosensors to cellular growth substrates. We have been exploring the potential of f-CNTs as delivery vehicles of biologically active molecules in view of possible biomedical applications, including vaccination and gene delivery. Recently we reported the capability of ammonium-functionalized single-walled CNTs to penetrate human and murine cells and facilitate the delivery of plasmid DNA leading to expression of marker genes. To optimize f-CNTs as gene delivery vehicles, it is essential to characterize their interactions with DNA. In the present report, we study the interactions of three types of f-CNTs, ammonium-functionalized single-walled and multiwalled carbon nanotubes (SWNT-NH3+; MWNT-NH3+), and lysine-functionalized single-walled carbon nanotubes (SWNT-Lys-NH3+), with plasmid DNA. Nanotube-DNA complexes were analyzed by scanning electron microscopy, surface plasmon resonance, PicoGreen dye exclusion, and agarose gel shift assay. The results indicate that all three types of cationic carbon nanotubes are able to condense DNA to varying degrees, indicating that both nanotube surface area and charge density are critical parameters that determine the interaction and electrostatic complex formation between f-CNTs with DNA. All three different f-CNT types in this study exhibited upregulation of marker gene expression over naked DNA using a mammalian (human) cell line. Differences in the levels of gene expression were correlated with the structural and biophysical data obtained for the f-CNT:DNA complexes to suggest that large surface area leading to very efficient DNA condensation is not necessary for effective gene transfer. However, it will require further investigation to determine whether the degree of binding and tight association between DNA and nanotubes is a desirable trait to increase gene expression efficiency in vitro or in vivo. This study constitutes the first thorough investigation into the physicochemical interactions between cationic functionalized carbon nanotubes and DNA toward construction of carbon nanotube-based gene transfer vector systems.     

The synthesis and characterisation of a novel dendritic system for gene delivery

There has been increasing interest in recent years in gene delivery. We report the synthesis of non-viral delivery systems composed of variations of the cell penetrating peptide TAT, a nuclear localisation signal peptide and dendritic polylysine. The delivery systems were tested for their ability to form complexes with plasmid DNA by utilising gel shift analysis, isothermal titration calorimetry, particle size analysis, zeta potential and transmission electron microscopy. These techniques indicated the successful formation of complexes between the peptide dendrimer and DNA.     

纳米阳离子多聚物在基因载体系统的应用

阳离子多聚物能与DNA通过静电吸附作用而自组装成纳米微粒,防止DNA被核酸酶降解.阳离子多聚物由于具备合成简便、储存稳定、基因荷载率高、靶向性强、免疫原性低等优点而被用作基因载体.阳离子多聚物按特性可分为两类：合成型和天然型.经典的人工合成型阳离子多聚物基因载体主要有：多聚乙烯亚胺、多聚左旋赖氨酸和树状大分子等;天然生物型阳离子多聚物基因载体主要有壳聚糖及其衍生物和明胶等.本文详细论述了各种阳离子聚合物用作基因载体的性能特点、自身缺陷、介导基因进入细胞的机理和靶向性策略,并对非病毒基因载体的发展作出展望.     

Core–Shell Structured Chitosan-Polyethylenimine Nanoparticles for Gene Delivery: Improved Stability,Cellular Uptake,and Transfection Efficiency

The delivery of nucleic acids relies on vectors that condense and encapsulate their cargo. Especially nonviral gene delivery systems are of increasing interest. However, low transgene expression levels and limited tolerability of these systems remain a challenge. The improvement of nucleic acid delivery using depolymerized chitosan–polyethylenimine DNA complexes (dCS-PEI/DNA) is investigated. The secore complexes are further combined with chitosan-based shells and functionalized with polyethylene glycol (PEG) and cell penetrating peptides. This modular approach allows to evaluate the effect of functional shell components on physicochemical particle characteristics and biological effects. The optimized ternary complex combines a core-dCS-linear PEI/DNA complex with a shell consisting of dCS-PEG-COOH, which results in improved nucleic acid encapsulation, cellular uptake and transfection potency in human hepatoma HuH-7cells and murine primary hepatocytes. Effects on transgene expression are confirmed in wild-type mice following retrograde intrabiliary infusion. After administration of only 100 ng complexed DNA, ternary complexes induced a high reporter gene signal for three days. It is concluded that ternary coreshell structured nanoparticles comprising functionalized chitosan can be used for in vitro andin vivo gene delivery.     

Improvement of the quality of self assembled bilayer lipid membranes by using a negative potential

Cell electropermeabilization (also termed cell electroporation) is nowadays a routine technique used in biochemical and pharmacological studies for the in vitro introduction of nonpermeant molecules into living cells. But electric pulses can be used as well in vivo for the delivery of drugs or DNA into cells of tissues. This review then gives an updated overview of the therapeutic perspectives of cell electropermeabilization in vivo, in particular of the antitumour electrochemotherapy (i.e., the combination of a cytotoxic nonpermeant drug with permeabilizing electric pulses delivered to the tumours) and of in vivo DNA electrotransfer for gene therapy. After a short summary of the present knowledge on cell electropermeabilization (particularly in vivo), the basis, the present achievements, and the challenges of electrochemotherapy are described and discussed, which includes an overview of still open questions and an update on recent clinical trials. DNA electrotransfer for gene therapy is an emerging field in which results are rapidly accumulating. Present knowledge on DNA electrotransfer mechanisms, as wel as the potentialities of DNA electrotransfer to become an efficient non-viral approach for gene therapy, are reviewed.     

Self‐Assembled DNA Nanoclews for the Efficient Delivery of CRISPR–Cas9 for Genome Editing

CRISPR–Cas9 represents a promising platform for genome editing, yet means for its safe and efficient delivery remain to be fully realized. A novel vehicle that simultaneously delivers the Cas9 protein and single guide RNA (sgRNA) is based on DNA nanoclews, yarn‐like DNA nanoparticles that are synthesized by rolling circle amplification. The biologically inspired vehicles were efficiently loaded with Cas9/sgRNA complexes and delivered the complexes to the nuclei of human cells, thus enabling targeted gene disruption while maintaining cell viability. Editing was most efficient when the DNA nanoclew sequence and the sgRNA guide sequence were partially complementary, offering a design rule for enhancing delivery. Overall, this strategy provides a versatile method that could be adapted for delivering other DNA‐binding proteins or functional nucleic acids.     

Gene delivery by electroporation after dielectrophoretic positioning of cells in a non-uniform electric field

We report the use of dielectrophoresis (DEP) to position U-937 monocytes within a non-uniform electric field, prior to electroporation (EP) for gene delivery. DEP positioning and EP pulsing were both accomplished using a common set of inert planar electrodes, micro-fabricated on a glass substrate. A single-shell model of the cell's dielectric properties and finite-element modeling of the electric field distribution permitted us to predict the major features of cell positioning. The extent to which electric pulses increased the permeability of the cell membranes to fluorescent molecules and to pEGFPLuc DNA plasmids were found to depend on prior positioning. For a given set of pulse parameters, EP was either irreversible (resulting in cytolysis), reversible (leading to gene delivery), or not detectable, depending on where cells were positioned. Our results clearly demonstrate that position-dependent EP of cells in a non-uniform electric field can be controlled by DEP.     

Lipophilic Tetranuclear Ruthenium(II) Complexes as Two‐Photon Luminescent Tracking Non‐Viral Gene Vectors

Fluorescence detection is the most effective tool for tracking gene delivery in living cells. To reduce photodamage and autofluorescence and to increase deep penetration into cells, choosing appropriate fluorophores that are capable of two‐photon activation under irradiation in the NIR or IR regions is an effective approach. In this work, we have developed six tetranuclear ruthenium(II) complexes, GV1–6 , and have studied their one‐ and two‐photon luminescence properties. DNA interaction studies have demonstrated that GV2–6 , bearing hydrophobic alkyl ether chains, show more efficient DNA condensing ability but lower DNA binding constants than GV1 . However, the hydrophobic alkyl ether chains also enhance the DNA delivery ability of GV2–6 compared with that of GV1 . More importantly, we have applied GV1–6 as non‐viral gene vectors for tracking DNA delivery in living cells by one‐ and two‐photon fluorescence microscopies. In two‐photon microscopy, a high signal‐to‐noise contrast was achieved by irradiation with an 830 nm laser. This is the first example of the use of transition‐metal complexes for two‐photon luminescent tracking of the cellular pathways of gene delivery and as DNA carriers. Our work provides new insights into improving real‐time tracking during gene delivery and transfection as well as important information for the design of multifunctional non‐viral vectors.